Subcutaneous infusion reservoir and pump system

ABSTRACT

A totally subcutaneously implantable infusion reservoir and pump system includes a variable capacity reservoir for receiving and storing fluid medication for delivery to a catheter which directs the medication to a specific infusion location in the body. In a preferred form of the invention, a control assembly is interposed between the reservoir and the catheter to facilitate and control the transfer of the medication from the reservoir to the catheter in a safe and efficient manner. This control assembly includes a normally closed valve and a pump, both of which are manually actuable by percutaneous pressure when subcutaneously implanted, and defines a portion of a fluid flow conduit between the reservoir and the catheter. Moreover, the control assembly is constructed to prevent the backflow of fluid from the catheter to the reservoir, as well as the unrestricted flow of medication through the control assembly when the normally closed valve is opened. This is accomplished by requiring at least two deliberate and sequential applications of selective pressure to the control assembly before any medication stored in the reservoir can be transferred to the catheter.

RELATED APPLICATION

This is a continuation of application Ser. No. 850,943, filed Apr. 11,1986, now U.S. Pat. No. 4,681,560, which is a continuation-in-part ofapplication Ser. No. 590,349, filed Mar. 16, 1984, now U.S. Pat. No.4,588,394.

BACKGROUND OF THE INVENTION

This invention relates generally to infusion systems for theadministration of medications and, more particularly, to a refillableand subcutaneously implantable infusion reservoir and pump system usefulfor pain management in the treatment of terminally ill patients.

It has been found in the treatment of many terminally ill patients thatthe administration of various medications over sustained periods of timeis necessary. For instance, it is often desirable to provide a painkiller, such as morphine, to such patients to help them cope with thesometimes excruciating pain which accompanies certain diseases.Frequently, terminally ill patients experience such extreme pain thathospitalization becomes necessary to provide the patient medications atintervals and in quantities sufficient to meet the patient's needs.Alternatively, when hospitalization is not acceptable, the patient isoften required to obtain private nursing care.

Requiring a terminally ill patient to either be hospitalized or toarrange for private nursing care can result in substantial burdens beingimposed upon both the health care system and the patient. Health carefacilities are increasingly burdened as the demand for hospital bedspace increases at a rate greater than the growth in available bedspace. This burden is accentuated when patients, such as terminally illpatients, are hospitalized for want of an alternative treatmentmethodology. Also, the diversion of medically trained personnel to dealwith the routine infusion of medications to terminally ill patientsimposes additional burdens on the health care system which could beavoided, provided the proper technology were available.

When patients must be confined to a hospital bed or arrange for privateduty nursing care to receive prescribed medications, the costs involvedoften exceed the financial means of such patients. For example, manyterminally ill patients cannot afford to pay for the very expensive andindividualized care which could make the last period of time prior todeath much more productive and less difficult for the patient and forthose around him. Indeed, some patients cannot afford any medical carewhatsoever and their only available alternative is to foregoin treament.Sometimes patients who cannot afford the hospitalization or privatenursing care required and who cannot tolerate the pain involved with aparticular disease must be hospitalized at society's expense.

These burdens to the patient, the health care system and to society ingeneral have prompted several changes in health care methodology. Forinstance, many physicians have found it desirable to administerprescribed medications on an out-patient basis. This out-patienttechnique has proven to be effective in substantially reducing the costsassociated in the treatment of many typs of ailments; however, therehave been a number of drawbacks which have made such out-patientarrangements less then ideal.

A typical drawback of out-patient treatment programs includes therequirement of frequent visits by the patient with the physician and theresultant time and transportation problems. It is generally recognizedthat if the patient could be provided adequate home care for extendedperiods of time, the time between visits with the physician could belengthened. Such extended home care would benefit the physician, as wellas the patient, in many circumstances by permitting the physician todevote more professional time to other important matters.

Notwithstanding the foregoing, some patients find that receiving regularinjections of medications over a prolonged period of time isdistasteful, not to mention painful. Additionally, it has been foundthat repeated injections through the skin into a specific, limited areaof the body can be harmful to the patient and can sometimes causeproblems which could become more threatening to he well-being of thepatient than the illness being treated. Such problems have madenecessary the use of alternate injection sites, the rotation ofinjections among alternate injection sites, or, at the extreme, theabandonment of medication injections as a useful form of treatment.

Moreover, some substances have been found to traumatize the skin wheninjected, and this has necessitated the use of alternate means forintroducing such substances into the body. Such alternate introductionmeans have included the use of catheters which are inserted through theskin into the body and have a portion which remains extended through thepatient's skin to provide external access. This and similar methods andsystems have proven to be undesirable for extended treatment because ofthe risk of infection at the incision site where the catheter extendsthrough the skin.

Accordingly, there has been a need in the medical arts for a system,including the appropriate devices, which allows the patient or his lovedones to administer required medications in precise quantities whileminimizing the number of injections required and visits which need bemade with a physician. Such a system should be constructed for totalsubcutaneous emplacement in the body, include appropriate devices toprevent the unintended infusion of the medications from the system intothe body, and be refillable, such as by injection, to permit long termuse. The present invention fulfills these needs and provides otherrelated advantages.

SUMMARY OF THE INVENTION

The present invention resides in an infusion reservoir and pump systemuseful, for example, in the administration of medications to patientsrequiring infusions of medications at relatively frequent intervals andover extended periods of time. More particularly, the system is usefulin the administration of pain killers directly into the central nervoussystem of terminally ill patients. In accordance with the presentinvention, the system, which is constructed for subcutaneous placementwithin the patient's body, generally includes a variable capacityreservoir which receives and stores the medications to be administered,a catheter which can be positioned to direct the medications to aselected portion of the patient's body, and a pump and valvingarrangement useful for transferring the medications from the reservoirto the catheter and for preventing the unintended passage of themedications from the reservoir into the catheter for delivery to thepatient.

In the illustrated embodiment, an injection site apparatus capable ofreceiving the medications to be infused into the patient by injection ispositioned separately within the patient with respect to the reservoir,and is connected thereto by surgical tubing. The injection siteapparatus includes a self-sealing dome and a relatively rigid base,which dome and base enclosed an injection chamber. Fluid medicationinjected into the injection chamber freely flows through the surgicaltubing from the injection site apparatus to the reservoir to fill thesame. An outlet of the injection site apparatus includes a one-way valveto prevent any reverse flow of fluid from the reservoir to the injectionchamber.

The pump and valving arrangement preferably forms a portion of a fluidflow conduit between the reservoir and the catheter, and is shown as acontrol assembly having a normally closed valve and a pump, both ofwhich are manually actuable by percutaneous pressure when subcutaneouslyimplanted. In a manner similar to that disclosed in my copending U.S.patent application Ser. No. 590,349, the entirety of which isincorporated herein by reference, the normally closed valve is coactivewith the pump to require at least two deliberate and sequentialapplications of selective pressure to the control assembly before themedication stored in the reservoir can be transferred to the catheter.More specifically, the pump and valving arrangement requires adeliberate and sequential, two-step procedure to fill and empty apumping chamber within the pump. This procedure makes the inadvertentintroduction of medication into the patient highly unlikely.

The illustrated control assemblies provide this safeguard with theinclusion of an integral flow occluder which is constructed andpositioned with respect to the normally closed valve to inherentlyprevent the outflow of fluid from the control assembly when the normallyclosed valve is opened. Only after the selective pressure has beenremoved from the normally closed valve, can fluid be forced from thepump, again through the selective application of pressure, and out thecontrol assembly for delivery to the catheter. Additionally, the controlassembly includes a one-way valve within the assembly outlet to preventany reverse flow of fluid from the catheter into the pump.

In a preferred form, the normally closed valve utilizes a flexible andresiliently biased valve diaphragm to generally underlie and close avalve passageway within the normally closed valve. This valve diaphragmcan be displaced to uncover the valve passageway by applyingpercutaneous pressure to an overlying cover of the normally closed valvein a manner insuring closure of the integral flow occluder. In anotherpreferred form, the normally closed valve includes a housing constructedor a resiliently flexible maerial, which encloses a rigid valve stemextending through the valve passageway. This stem is normally biased toprevent flow through the valve passageway unless forceably displaced.

The catheter can be inserted into any portion of the body, such as thelateral ventricle of the brain or the lumbar subarachnoid space. Ineither of these exemplary configurations, the system provides anefficient and convenient apparatus and method for the administration ofmedications directly into the central nervous system of terminally illpatients. While such catheter placements are presently contemplatedprimarily to enhance the treatment of terminally ill patients, it isconceivable that the infusion reservoir and pump system of the presentinvention could be useful in other medical applications; for instance,in the administration of insulin to diabetic patients.

In addition to the use of standard surgical tubing, the variouscomponents of the system of the present invention may be placed in fluidcommunication with each other through use of flexible, substantiallyinelastic materials such as Teflon tubing by means of a frictionconnector assembly. The particular friction connector assemblyillustrated herein utilizes an elastic silicone sleeve which iscompressed to securely hold an end of the substantially inelastic tubingwithin the connector assembly.

When the system of the present invention is surgically emplacedsubcutaneously within a patient, it is deemed generally preferable tolocate the injection site apparatus and the reservoir near softer areasof the body where the skin can be manipulated to allow the injectionsite apparatus and the reservoir to be percutaneously grasped.Typically, the reservoir will be located in a position remote from thecatheter in the abdominal cavity, below the ribs, near a clavicle, or inany other suitable position the surgeon may choose.

Besides forming a single, integral control assembly, the pump andvalving arrangement can be constructed from separate, coactivecomponents, each forming independent portions of the fluid flow conduitleading from the reservoir to the catheter. Notwithstanding theconfiguration of the pump and valving arrangement, it is preferable tolocate each component of such generally adjacent a boney surface toprovide the desired resistance to movement when the components arepercutaneously manipulated. For instance, the pump and valvingarrangement could be located adjacent a rib, a clavicle or an iliaccrest depending on the insertion point of the catheter and thepreferences of the surgeon.

Other features and advantages of the present invention will becomeapparent from the following more detailed description, taken inconjunction with the accompanying drawings which illustrate, by way ofexample, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate the invention. In such drawings:

FIG. 1 is a diagrammatic view of a preferred form of the presentinvention, illustrating the relationship of the various components toeach other, and showing a portion of the reservoir shell broken away andthe fluid flow path through the pump and valving arrangement in phantomfor clarity;

FIG. 2 is an enlarged, fragmented sectional view taken generally alongthe line 2--2 of FIG. 1, illustrating the configuration of a controlassembly forming the pump and valving arrangement when ready for pumpingmedication to the patient;

FIG. 3 is an enlarged, fragmented sectional view, similar to FIG. 2, ofthe control assembly, illustrating the manner in which fluid is pumpedfrom a pumping chamber to the catheter;

FIG. 4 is an enlarged, fragmented sectional view, similar to FIGS. 2 and3, of the control assembly, illustrating the manner in which thenormally closed valve is opened to permit the filling of the pumpingchamber while simultaneously preventing the flow of fluid out of thecontrol assembly through the provision of an integral flow occluder;

FIG. 5 is an enlarged, fragmented sectional view taken generally alongthe angulated line 5--5 of FIG. 1, illustrating more clearly the inletto the normally closed valve;

FIG. 6 is an enlarged sectional view of an alternate form of thenormally closed valve, this particular view illustrating the manner inwhich the alternate normally closed valve would be attached to a pump toform an alternate control assembly if sectioned along the line 2--2 ofFIG. 1;

FIG. 7 is an enlarged, fragmented sectional view taken generally alongthe line 7--7 of FIG. 1, illustrating an injection site apparatus and aportion of a variable capacity reservoir connected to the injection siteapparatus by flexible tubing; and

FIG. 8 is an enlarged, fragmented and partially sectional view of afriction connector which can be used with the system of the presentinvention to connect flexible, substantially inelastic tubing betweenthe other components to place the same in fluid communication with oneanother.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in the drawings for purposes of illustration, the presentinvention is concerned with a subcutaneous infusion reservoir and pumpsystem, generally designated by the reference number 10. This infusionreservoir and pump system 10 generally comprises a variable capacityreservoir 12 connected by a fluid flow conduit 14 to a catheter 16 whichdirects medications stored in the reservoir to a specific locationwithin the patient. A pump and valving arrangement 18 is also providedto prevent or reduce the likelihood of an inadvertent infusion into thepatient of medications stored in the reservoir 12.

The pump and valving arrangement 18 used in the system 10 can besituated between the reservoir 12 and the catheter 16 to form a portionof the fluid flow conduit 14, and the pump and valving arrangement caninclude one or more normally closed valves. Such a system would requirefluid medication to flow through the pump and valving arrangement 18before passing into the catheter 16, and with the safety well-being ofthe patient an all-important consideration in the employment of thesystem 10, this flow path requirement provides the control over the flowof the medication which is critical to the system's safe use. Indeed, apump and valving arrangement can be provided which practicallyeliminates the chance of inadvertently infusing more than a very smallquantity of medication into the patient, by requiring specificsequential deliberate steps to be taken before a measured volume offluid can be pumped through the system 10.

The subcutaneous infusion reservoir and pump system 10 can substantiallyreduce the cost of treating some illnesses by eliminating the need forconstant medical attention or by reducing the number of required visitswhich need be made with a physician. The overall design of the system 10increases its utility for physicians and patients in that the system canbe constructed in a variety of configurations for use in many types ofdifferent applications. Additionally, the system 10 may be usedadvantageously by patients requiring regular infusions by minimizing thenumber of injections received. Moreover, the inherent safety and utilityof the infusion reservoir and pump system 10 will permit a patient'sfamily or other loved ones to care for the patient in the privacy of thehome and, particularly for terminally ill patients, make the period ofillness much more productive and less difficult for the patient andthose around him.

In accordance with the present invention, and as illustrated withrespect to a preferred embodiment in FIGS. 1-5 and 7, the variablecapacity reservoir 12 comprises a silicone elastomer shell 20 which canexpand and collapse to accommodate changing volumes of fluidmedications. The reservoir 12 includes inlet and outlet apertures 20 and22 through the reservoir shell 20, which apertures are positioned topermit passage therethrough of flexible tubing, such as surgical tubing.More particularly, a segment of flexible tubing 26 is passed through theinlet aperture 22, and a seal is formed in a conventional manner betweenthe flexible tubing and that portion of the reservoir shell 20surrounding the inlet aperture. The flexible tubing 26 extens from apoint approximately midway through the interior of the reservoir 12,through the inlet aperture 22, and to an independently positionableinjection site apparatus 28 which will be described in further detailbelow. Another segment of flexible tubing 30 likewise extends fromapproximately the center of the reservoir 12, through the outletaperture 24, to a control assembly 32 forming the pump and valvingarrangement 18 mentioned above, which control assembly will also befurther discussed below. The portion of the reservoir shell 20surrounding the outlet aperture 24 is sealed in a conventional manner tothe flexible tubing 30 to prevent the escape of any fluids from thereservoir 12 except through the flexible tubing 30.

Those portions of the flexible tubing 26 and 30 situated within thevariable capacity reservoir 12 include a plurality of tube apertures 34.The positioning of the flexible tubing 26 and 30 so that each extendsfrom approximately the center of the reservoir 12, together with theprovision of the tube apertures 34, helps insure that a flexible tubefluid passageway will be provided through the center of the reservoirfor channeling fluid medications into or out of the reservoirnotwithstanding a collapse of the reservoir shell 20. To this end, theflexible tubing is preferably constructed of a resilient siliconeelastomer material. For example, the portion of the flexible tubing 30situated within the reservoir 12 insures that fluid medications will beable to exit the reservoir 12 even when the reservoir shell 20 collapsesin a manner which would otherwise occlude the outlet aperture 24.

In systems 10 designed for use in the treatment of terminally illpatients, a reservoir 12 having a thirty milliliter capacity wouldnormally hold sufficient amounts of morphine or other similar painkilling drugs to supply patients sufficient quantities of medicationsfor several days. The variable capacity reservoir 12 can be remotelylocated from the insertion point of the catheter 16 in any suitableposition as the surgeon chooses, such as in the abdominal cavity, belowthe ribs or near the clavicle. Indeed, the reservoir 12 can be placed inany soft area of the body which would permit the reservoir to bepercutaneously grasped while subcutaneously implanted. If necessary toaid in the positioning of the reservoir 12, suture tabs (not shown)could be integrally formed with the reservoir shell 20 to permit thesurgeon to anchor the reservoir 12 at the selected location within thepatient to prevent migration of the reservoir to an undesirablelocation.

The injection site apparatus 28 is shown as being separated from thereservoir 12, and in such a configuration the possibility of puncturingthe reservoir during injection with a needle 36, is eliminated. Theinjection site apparatus 28 includes a rigid polypropylene body 38forming a needle-shield for the injection site apparatus, and the bodyis securely mounted to a silicone elastomer base 40. The rigid body 38provides a funnel-like upper surface 42, which surface further includesindents 44 into which a peripheral rim 46 of an overlying self-sealingdome 48 is positioned to form a fluid-tight seal between the dome andthe rigid body. The self-sealing dome 48 is consructed of a siliconeelastomer material, such materials providing acceptable levels of tissuereaction when subcutaneously implanted, which can be pierced by atwenty-five gauge or smaller needle 36 without affecting the ability ofthe dome to re-seal after the needle has been withdrawn.

A channel 50 is provided through the base of the rigid body 38, whichchannel is aligned with a similar channel 52 through the base 40. Thesechannels 50 and 52 together form a fluid passageway extending from aninjection chamber 54 enclosed and defined by the self-sealing dome 48and the rigid body 38, to the flexible tubing 26. The flexible tubing 26includes an inlet end 56 sealingly secured within an outlet 58 of theinjection site apparatus 28 in a conventional manner to prevent theescape of fluids between the flexible tubing and the base 40. This inletend 56 of the flexible tubing 26 also includes a one-way valve 60situated therein to prevent any reverse flow of fluid from the reservoir12 back to the injection chamber 54. In such a configuration the reverseflow of fluid medication from the reservoir 12 into the injectionchamber 54 is prevented even when the fluid pressure within thereservoir is greater than the fluid pressure within the injectionchamber. This unidirectional flow feature provides a safety mechanismfor the system 10 which prevents the escape of medications stored withinthe reservoir 12 through the injection site apparatus 28, and minimizesproblems which could occur if medications began to leak through theself-sealing dome 48.

The silicone elastomer base 40 of the injection site apparatus 28 isfirmly affixed to a reinforced silicone sheet 62. This reinforced sheet62 helps give the entire injection site apparatus 28 an inherenttoughness which can withstand the multiple instances that such injectionsite apparatus will likely be percutaneously manipulated and piercedwith the needle 36. Moreover, this reinforced sheet 62 is affixed to theunderside of the base 40 to provide a sturdy peripheral flange for theinjection site apparatus 28, which flange in effect provides acontinuous suture tab to allow the surgeon to anchor the injection siteapparatus at the selected location within the patient to preventmigration of the injection site apparatus to an undesirable location.

Although the injection site apparatus 28 is illustrated in theaccompanying drawings as being remotely located from the reservoir 12,it can in fact be located in any suitable position as the surgeonchooses, including locations immediately adjacent the reservoir 12 inthe abdominal cavity, below the ribs or near the clavicle. Indeed, theinjection site apparatus 28 can be placed in any soft area of the bodywhich would permit the injection site apparatus to be percutaneouslygrasped while subcutaneously implanted.

It should be apparent that the flexible tubing 30 extending from thereservoir 12 to the control assembly 32 forms a portion of the fluidflow conduit 14 discussed briefly above. Although the flexible tubing 30extending from the reservoir 12 to the control assembly 32 is shown aspassing through the reservoir shell 20, connectors could easily beattached to the reservoir shell for connecting the flexible tubingexteriorly to the reservoir 12 by means of a friction seal.

As the fluid medications are transferred from the reservoir 12 throughthe fluid flow conduit 14 to the catheter 16, the medications passthrough the pump and valving arrangement 18. As illustrated in FIGS. 1through 5, the pump and valving arrangement 18 comprises the integralcontrol assembly 32 which is attached to the flexible tubing 30 carryingfluid medications that have exited the reservoir 12. The controlassembly 32 forms a portion of the fluid flow conduit 14 between thereservoir 12 and the catheter 16, and is situated so that a controlassembly inlet 64 is in open fluid communication with the reservoir 12,and a control assembly outlet 66 is in open fluid communication with thecatheter inlet.

The control assembly 32 provides a normally closed valve 68, a pump 70,a one-way inlet valve 72, and a one-way outlet valve 74 within the fluidflow conduit 14. These components of the control assembly 32 are soarranged with respect to each other as to require a sequential, two-stepapplication of selective percutaneous pressure when subcutaneouslyimplanted before permitting the passage of medication from the reservoir12 to the catheter 16. Moreover, because percutaneous pressure must beapplied to the assembly 32 to open the normally closed valve 68 whensubcutaneously implanted, it is preferable to locate the assemblygenerally adjacent a bone. Thus, in many instances the control assembly32 is provided suture tabs which allow the surgeon to anchor theassembly and insure that it remains in the location selected by thephysician.

The control assembly 32 is constructed to include a generally planar,rigid floor plate 76, and an overlying stiffly resilient, yet flexiblehousing 78. Affixed to a portion of the floor plate 76 is a relativelyrigid diaphragm support 80, which in turn supports a rigid diaphragm cap82. The support 80 and the cap 82 are situated and configured betweenthe housing 78 and the floor plate 76 to provide the normally closedvalve 68 an inlet chamber 84 in fluid communication with the assemblyinlet 64, an outlet chamber 86 which overlies the inlet chamber, and avalve passageway 88 (formed by the diaphragm cap 82) between the inletand outlet chambers.

A resiliently flexible valve diaphragm 90, constructed to form adome-shaped member, is seated circumferentially upon the diaphragmsupport 80 within the inlet chamber 84 so that a portion of thediaphragm is normally positioned adjacent the valve passageway 88. Thisvalve diaphragm 90 is provided a plurality of diaphragm apertures 92.Unless forceably displaced away from the portion of the cap 82surrounding the valve passageway 88, the diaphragm 90 forms a seal withthat adjacent portion of the cap, and prevents any fluid flow throughthe normally closed valve 68. It is preferred that the cap 82 and thediaphragm 90 be constructed of different materials which will not stickto one another, particularly after long periods of storage.

The portion of the housing 78 overlying the outlet chamber 86 includes adownwardly extending diaphragm displacement finger 94 positioneddirectly above the valve passageway 88. The finger 94 is situated fortravel through the valve passageway 88 when pressed downwardly, and thediameter of the lower portion of the finger is small enough to preventthe occlusion of the valve passageway when the finger is pressedtherethrough. When enough pressure is applied, the finger 94 causes thevalve diaphragm 90 to flex downwardly a sufficient distance to break thevalve seal and allow fluids to pass through the valve passageway 88(FIG. 4). The housing 78 and the valve diaphragm 90 are eachsufficiently resilient to return to their normal configurations and,consequently, close the normally closed valve 68 to fluid flow when thedeforming pressure is removed. The inclusion of such a normally closedvalve 68 in the system 10 enhances the system's utility and safety bypreventing the flow of fluids through the fluid flow conduit 14 in theabsence of direct, selectively applied percutaneous pressure on thecontrol assembly 32.

The pump 70, which receives fluids from the normally closed valve outletchamber 86, comprises a crown 96 formed by the housing 78, whichoverlies a substantial part of the floor plate 76 to enclose and definea pumping chamber 98. The pumping chamber 98 preferably has anevacuation capacity of one milliliter, and the crown 96, which isresiliently biased to generally maintain a dome or arch-shape, can bedeformed to lie substantially flat against the floor plate 76. Thevolume of the pumping chamber 98 can be customized to accommodatevarious intended uses for the system 10 and the required dosage to beinfused into the patient per pumping stroke. By constructing the housing78, and therefore the crown 96, of a silicone elastomer material,medication can be injected, if necessary, directly into the pumpingchamber 98, the floor plate 76 functioning as a needle guard, and thepuncture site will tend to close upon itself and seal the crown when theneedle 36 is removed.

A flexible occluder wall 100 is provided over that portion of thehousing 78 forming the normally closed valve 68, and defines, inconnection with the housing, a fluid exit passageway 102 from thepumping chamber 98 to the one-way valve 74. More specifically, fluidexiting the pumping chamber 98 typically flows through a common fluidpassage 104 which also acts as the pump inlet in the transfer of fluidsfrom the valve 68, then between the occluder wall 100 and the uppersurface 106 of that portion of the housing 78 overlying the outletchamber 86, and finally through an exit passage 108. The portion of thehousing 78 overlying the outlet chamber 86 and immediately adjacent theoccluder wall 100 is formed with several ridges 110 which help to form aseal with the occluder wall when pressed together to depress the finger94 through the valve passageway 88.

A hard protective valve sheath (sometimes called a support ring) 112generally surrounds those portions of the housing 78 wherein the one-wayoutlet valve 74 and the diaphragm 90 of the normally closed valve 68 aresituated, to protect the same from unintentional deformation which mightresult in the inadvertent passage of fluid through the control assembly32. As illustrated in the accompanying drawings, the only mannerprovided for opening the normally closed valve 68 is through theselective downward application of pressure on the occluder wall 100,which simultaneously occludes the fluid exit passageway 102 and preventsthe exit of fluid from the control assembly 32. Thus, only after thepressure is released from the occluder wall 100 and the valve 68 isclosed, can medication within the pumping chamber 98 be forced out ofthe control assembly 32 through the fluid exit passageway 102.

The one-way outlet valve 74 is situated near the assembly outlet 66 toprevent the inflow of fluid to the control assembly 32 through theassembly outlet. A control assembly outlet connector 114 extendsoutwardly from the housing 78 to define the assembly outlet 66. Thiscontrol assembly outlet connector 114 is designed to engage an inlet endof surgical tubing forming a portion of the fluid flow conduit 14, or,as illustrated, a catheter inlet 116. The end of the outlet connector114 situated within the housing 78 includes a flange portion 118 whichsealingly engages a suture sleeve 120 to form a seal preventingmedication from exiting the control assembly 32 other than through theoutlet connector.

While the pump and valving arrangement 18 is shown in the exemplarydrawings as combined to form the single control assembly 32, thenormally closed valve 68 and the pump 70 may be separately constructedto form individual system components which can be connected to oneanother by a conduit such as the flexible tubing 30.

The catheter 16 is preferably formed of a barium-impregnated siliconeelastomer material which is radiopaque for detection by X-rayphotography. The catheter inlet 116 is attached to the control assemblyoutlet connector 114 by sliding frictional engagement, and fluidmedication exiting the control assembly 32 is directed by the catheter16 for infusion into a specific portion of the body. For example, in thecase of terminally ill patients the catheter 16 can be inserted into thelateral ventricle of the patient's brain. When such catheter placementis contemplated, a catheter clip 122, as shown in FIG. 1, can beadvantageously utilized to hold the catheter 16 in place adjacent a burrhole through the skull.

The pump and valving arrangement 18 requires a two-step procedure topump fluid medication from the reservoir 12 to the catheter 16. Beforepumping may begin, however, the flexible tubing 26 and 30 between theinjection site apparatus 28 and the reservoir 12, and the reservoir andthe control assembly 32, must be primed with medication, and the salinesolution normally contained within the control assembly during insertioninto the patient must be evacuated therefrom. Typically, thispreparatory step can be accomplished by simply depressing the pump crown96 through the selective application of percutaneous pressure asillustrated in FIG. 3. This causes any fluid within the pumping chamber98 to exit the control assembly 32 through the fluid exit passageway 102as shown by the arrows. The membrane lips of the one-way outlet valve 74spread sufficiently to allow such fluid to escape the control assembly32, but immediately close and prevent the reverse flow of fluid throughthe fluid exit passageway 102 upon removal of the percutaneous pressuredepressing the pump crown 96. The valve diaphragm 96 and the one-wayinlet valve 72 prevent fluid within the pumping chamber 98 from passingback into the reservoir 12. After the pumping chamber 98 has beenevacuated, the normally closed valve 68 and the one-way outlet valve 74function collectively to prevent the refilling of the pumping chamberwith fluid from the catheter, and the diaphragm 90 prevents fluid fromflowing from the reservoir 12. Accordingly, the crown 96 remains in adepressed or collapsed position until the normally closed valve 68 isopened.

After this preparatory step has been completed, the pump 70 and valve 68can be repeatedly percutaneously manipulated to transfer measuredquantities of medication from the reservoir 12 to the catheter 16 forinfusion into a patient. To begin, the first step includes the selectiveapplication of pressure to the occluder wall 100 to depress the finger94 downwardly through the valve passageway 88 sufficiently to break theseal between the flexible valve diaphragm 90 and the adjacent portion ofthe cap 82. This permits fluid medication to flow from the inlet chamber84 through the valve passageway 88 into the outlet chamber 86, thenthrough the common passage 104 and into the pumping chamber 98. Thebiasing and resiliency of the pump crown 96 tends to draw the fluidmedication through the normally closed valve 68 to fill the pumpingchamber 98 until the crown 96 has resumed its dome or arch-shape (FIG.4). At times where the biasing and resiliency of the pump crown 96 isnot sufficient to cause fluid flow through the system 10, the reservoir12 can be percutaneously palpated to create adequate fluid pressurethrough the fluid flow conduit 14 to completely fill the pumping chamber98.

The construction of the control assembly 32 to include the occluder wall100 capable of preventing the flow of fluid through the fluid exitpassageway 108, adds an important safety feature to the infusionreservoir and pump system 10. As illustrated and described, there cannever be more than the volume of fluid contained within the pumpingchamber 98 which can pass through the control assembly 32 into thecatheter 16 each time the valve 68 is opened. Whenever the valve 68 isopened, the occluder wall 100 interacts with the ridges 110 to blockflow of medication through the fluid exit passage 108, and thus preventany medication from passing through the control assembly 32 while thepumping chamber 98 is being refilled. In essence, the control assembly32 provides a simplified pump and valving arrangement 18 within thefluid flow conduit 14 which never allows the reservoir 12 to be placedin opened communication with the catheter 16, and risk an excessivetransfer of medication through the system 10 to the patient.

After the pumping chamber 98 is filled with medication, the selectivepressure can be withdrawn from the occluder wall 100, allowing theresiliently biased valve diaphragm 90 to again become positioned toblock fluid flow through the valve passageway 88. To transfer themedication from the pumping chamber 98 through the control assembly 32to the catheter 16, the second step simply requires the selectiveapplication of pressure to depress the pump crown 96, to evacuatemedication from the pumping chamber 98 through the fluid exit passageway102 and out the assembly outlet 66. As described previously, the sealbetween the valve diaphragm 90 and the surrounding portion of the cap 82will prevent the passage of fluid in either direction through the valvepassageway 88 unless forcefully depressed by the displacement finger 94,and the one-way outlet valve 74 permits only the outflow of medicationor other fluids from the control assembly 32 as the crown 96 isdepressed. Once the pump crown 96 has been depressed toward theunderlying part of the floor plate 76, the pressure applied can bereleased, leaving the pump crown 96 in the deflected or depressedposition, and the control assembly 32 is once again ready for anotherpumping cycle which would begin with the opening of the normally closedvalve 68 through another selective application of percutaneous pressure.

It is evident from the foregoing that the sequential two-step pumpingprocedure described prevents the inadvertent infusion of medicationsthrough the system 10 which could result in harm to the patient. All ofthese foregoing features evident from the description of theabove-described subcutaneous infusion reservoir and pump system 10, canbe found in a modification of the control assembly 32 to include analternate-type of normally closed valve 124.

As illustrated in FIG. 6, the modified control assembly 32' isconstructed and operates in a manner very similar to that of theabove-described control assembly 32. More specifically, the modifiedcontrol assembly 32' is constructed to include a generally planar, rigidfloor plate 76', and an overlying stiffly resilient, yet flexiblehousing 78'. The housing 78' is configured to provide the alternatenormally closed valve 124 an inlet chamber 84' in fluid communicationwith an assembly inlet 64', an outlet chamber 86' which overlies theinlet chamber, and a valve passageway 88' between the inlet and outletchambers.

As was the case with the embodiment illustrated in FIG. 1, the flexiblehousing 78' can be constructed of a silicone elastomer material in amanner permitting the housing to re-seal if punctured by a needle. Themodified assembly inlet 64' is configured to internally receive an endof the flexible tubing 30, which in turn is fused within the inlet toplace the modified control assembly 32' in open fluid communication withthe reservoir 12. Fluid flowing through the assembly inlet 64' initiallyenters the inlet chamber 84' formed between the flexible housing 78' andthe floor plate 76'. Fluid within the inlet chamber 84' must await theopening of the alternate normally closed valve 124 before flowing intothe pump 70'.

The outlet chamber 86', which is in open fluid communication with thepump 70', is provided within the normally closed valve 124. A portion ofthe outlet chamber 86' is situated to generally overlie the inletchamber 84' so that the valve passageway 88' through an intermediateportion 126 of the housing 78' can provide a fluid flow path between theinlet chamber 84' and the outlet chamber 86'. The intermediate portion126 of the housing 78' generally surrounding this valve passageway 88'has a lower tapered surface which forms a valve seat 128.

A generally T-shaped valve stem 130 is provided within the valve passage88' extending from the outlet chamber 86' through the valve passageway88' and into the inlet chamber 84'. The valve stem 130 includes an upperexpanded section 132 which is securely attached to an upper ceiling ofthe outlet chamber 86' in a manner causing the valve stem 130 to move inresponse to any movement of the upper ceiling surface. The valve stem130 also includes a shaft 134 which extends downwardly from the upperexpanded section 132 through the valve passageway 88' and into the inletchamber 84' where this shaft enlarges slightly to form a lowered taperedfoot 136 having a shape which cooperates with the taper of the valveseat 128. In the normally closed position, this lower foot 136 contactsthe valve seat 128 to seal the valve passageway 88' and prevent fluidflow between the inlet chamber 84' and the outlet chamber 86'. Theoutlet chamber 86' is also sufficiently large to accommodate movement ofthe upper expanded section 132 of the valve stem 130 and still permitfluid flow therethrough. The valve stem 130 is constructed of a materialdifferent from the material of the housing 78' to reduce valve seat tovalve stem sticking. For instance, the valve stem 130 can be constructedof a polypropylene material to reduce the possibility of sticking to asilicone elastomer valve seat 128 during storage, handling, shipping oruse of the valve 124.

With the exception of the foregoing noted differences between themodified control assembly 32' illustrated in FIG. 6, and the controlassembly 32 illustrated in FIG. 1, the construction and operation of therespective control assemblies are identical. To illustrate the point,the pump 70', which receives fluid from the alternate normally closedvalve outlet chamber 86', comprises a crown 96' formed by the housing78', which overlies a substantial part of the floor plate 76' to encloseand define a pumping chamber 98'. The pumping chamber 98' alsopreferably has an evacuation capacity of one milliliter, and the crown96', which is resiliently biased to generally maintain a dome orarch-shape, can be deformed to lie substantially flat against the floorplate 76'.

A flexible occluder wall 100' is provided over that portion of thehousing 78' forming the alternate normally closed valve 124, anddefines, in connection with the housing and a hard, protective valvesheath 112', a fluid exit passageway 102' from the pumping chamber 98'to the one-way outlet valve 74'. More specifically, fluid exiting thepumping chamber 98' typically flows through a common fluid passage 104'which also acts as the pump inlet in the transfer of fluids from thevalve 68', then between the occluder wall 100' and the upper surface106' of that portion of the housing 78' overlying the outlet chamber86', and finally through an exit passage 108'. That portion of thehousing 78' overlying the outlet chamber 86' and immediately adjacentthe occluderwall 100' is formed with several ridges 110' which help toform a seal with the occluder wall when pressed together to move thevalve stem 130 through the valve passageway 88', and separate the lowertapered foot 136 from the valve seat 128 to open the valve 124.

The sheath (sometimes called a support ring) 112', generally surroundsthose portions of the housing 78' wherein the one-way outlet valve 74'and the valve stem 130 of the normally closed valve 124 are situated, toprotect the same from unintentional deformation which might result inthe inadvertent passage of fluid through the alternate control assembly32'. The only manner provided for opening the alternate normally closedvalve 124 is through the selective downward application of pressure onthe occluder wall 100', which simultaneously occludes the fluid exitpassageway 102' and prevents the exit of fluid from the modified controlassembly 32'. Thus, only after the pressure is released from theoccluder wall 100' and the valve 124 is closed, can medication withinthe pumping chamber 98' be forced out of the control assembly 32'through the fluid exit passageways 102' and 108'.

Although the various individual components of the subcutaneous infusionreservoir and pump system 10 illustrated in the accompanying drawingswill typically be connected to one another by surgical tubing eitherfused within inlet and exit openings, or frictionally connected to oneor more connector assemblies, the present invention further contemplatesuse of flexible, substantially inelastic tubing, such as tubingconstructed of the material known as Teflon. To this end, and asillustrated in FIG. 8, a different type of connection between theinelastic tubing to the various components is preferably utilized, sinceit may be undesirable to glue or otherwise fuse the inelastic tubing tothe adjacent component, and such alternate flexible tubing further lacksthe elasticity necessary to slide over standard connector assemblies toform a frictional fit therewith.

The connector assembly 138 includes generally a connector body 140 and acorresponding connector nut 142. The connector body 140 includes one endpositioned and securely held within an inlet or exit opening of any ofthe system 10 components in a standard fashion, an enlarged portion 144provided indents 146 intended to provide a secure gripping surface tofacilitate handling of the same by the surgeon, and a threaded endportion 148 extending outwardly away from the enlarged portion oppositethe component of the system 10 to which the connector body 140 isattached. The connector nut 142 includes an internally threaded portion150 dimensioned to correspond with the threaded end portion 148 of theconnector body 140. A generally cylindrical chamber 152 is providedwithin the connector nut 142 inwardly of the internally threaded portion150, wherein a resiliently flexible and elastic sleeve 154 ispositioned.

When assembled, the connector body 140, the connector nut 142 and thesleeve 154 provide, in combination, a connector assembly fluidpassageway 156 capable of channeling fluids from the adjacent systemcomponent to a segment of inelastic tubing. Such tubing, illustrated inFIG. 8 by the reference number 158, is inserted into the connectorassembly 138 through an aperture 160 through the distal end of theconnector nut 142, and may extend the entire length of the connectorassembly passageway 156.

The tubing 158 is held within the connector assembly 138 by a grippingaction exerted on the tubing by the sleeve 154 as it is compressedbetween the cylindrical chamber 152 of the connector nut 142, and thethreaded end portion 148 of the connector body 140. In particular, thesleeve 154 is dimensioned to extend a short distance into the internallythreaded portion 150 so that as the connector nut 142 is threaded ontothe connector body 140, the engaging end of the threaded portion 148presses the sleeve 154 back into the cylindrical chamber 152. Thisaction causes the elastic sleeve to slightly expand against the outerwall of the adjacent tubing 158 a sufficient amount to form a sealbetween the sleeve and the tubing, and further securely hold the tubingin place. The provision of such a connector assembly 138 gives thesurgeon greater flexibility in determining precisely how the variouscomponents of the system 10 will be implanted within the patient, andfurther the manner in which the various components will be fluidlyconnected to one another.

The infusion reservoir and pump system 10 described above can greatlyease the burden of medical personnel and hospital facilities byproviding means for internally storing a large quantity of medicationwhich is to be administered to a patient over an extended period oftime. Moreover, various apparatuses can be added to the system 10 for amultitude of purposes, such as the provision of a burr hole reservoirsituated adjacent the skull to facilitate injection of medicationsdirectly into the brain.

Although a particular embodiment of the invention and alternatecomponents forming portions thereof have been described in detail forpurposes of illustration, various modifications of the system as a wholeand the components individually may be made without departing from thespirit and scope of the invention. Accordingly, the invention is not tobe limited, except as by the appended claims.

We claim:
 1. A subcutaneous infusion reservior and pump system,comprising:means for receiving medication into said system by injection;a reservoir fluidly connected to said receiving means in a mannerpermitting the subcutaneous transfer of medication from said receivingmeans to said reservoir; a catheter for directing the medication to aspecific location in a body removed from said reservoir, said catheterhaving a catheter inlet and being positionable within the bodyindependently of the position of said reservoir; means forsubcutaneously conducting the medication from said reservoir to saidcatheter inlet; means for pumping and controlling the flow of medicationfrom said reservoir to said catheter, said pumping and controlling meansforming a portion of said conducting means and including normally closedvalve means and a pump which is separated from said reservoir and saidcatheter by other portions of said conducting means, wherein saidnormally closed valve means includes a body defining a fluid flowpassageway therethrough, and a valve member positioned within the fluidflow passageway to occlude the valve means; and means for occluding anoutlet of said pumping and controlling means when said normally closedvalve means is opened to fluid flow therethrough.
 2. A system as recitedin claim 1, wherein the valve member comprises a dome-like diaphragmresiliently biased to occlude at least a portion of the fluid flowpassageway of the valve means.
 3. A system as recited in claim 1,wherein said occluding means includes an occluder wall overlying anupper portion of said normally closed valve means, said occluder walldefining, in connection with an adjacent portion of said normally closedvalve means, a fluid exit passageway in communication with an outlet ofsaid pump, said occluder wall preventing the flow of fluid through saidfluid exit passageway when pressed against the adjacent portion of saidnormally closed valve means.
 4. A system as recited in claim 3, whereinsaid normally closed valve means is integrally formed with a resilientcrown which defines an upper portion of the pump.
 5. A system as recitedin claim 1, wherein said receiving means comprises an injection siteapparatus having a self-sealing dome overlying a rigid needle-shield todefine an injection chamber therebetween, said needle-shield having anoutlet passageway in open fluid communication with an outlet of saidinjection site apparatus so that said reservoir is placed in fluidcommunication with said injection chamber when the fluid pressure withinthe injection chamber exceeds the fluid pressure within the reservoir.6. A system as recited in claim 5, wherein said reservoir includes aflexible outer body capable of expanding to accommodate varying amountsof medication.
 7. A system as recited in claim 2, wherein said pumpincludes a pump inlet, a pump outlet, and a resilient crown overlying afloor plate to define a pumping chamber therebetween, said pump beingactuated through manual percutaneous pressure applied to said resilientcrown when subcutaneously implanted.
 8. A system as recited in claim 1,including a one-way valve situated within said conducting means, saidone-way valve causing fluid flow through said conducting means to beuni-directional.
 9. A subcutaneous infusion reservoir and pump system,comprising:means for receiving medication into said system by injection;a reservoir for storing medication injected into said receiving means; anormally closed valve capable of being opened to fluid flow therethroughby percutaneous manual manipulation and having a valve inlet in fluidcommunication with said reservoir, a valve outlet, a resilientlyflexible housing forming an inlet chamber and an outlet chamber, a valvepassageway situated directly between said inlet and outlet chambers,said valve passageway permitting fluid flow between said inlet andoutlet chambers, and a valve diaphragm situated within said housing andresiliently biased to cover said valve passageway, said valve diaphragmnormally forming a seal with a portion of said valve surrounding saidvalve passageway to prevent the flow of fluid through said normallyclosed valve unless forceably displaced; a pump placed in fluidcommunication with said valve, the pump having a pump inlet, a pumpoutlet and a resilient crown defining at least a portion of said pumpingchamber, said pump being manually actuable by the selective applicationof percutaneous pressure to depress said crown; means for occluding saidpump outlet when said normally closed valve is opened to fluid flowtherethrough, said means for occluding including an occluder walloverlying the top portion of said housing of said normally closed valve,said occluder wall defining, in connection with the adjacent portion ofsaid housing, a fluid exit passageway in communication with said pumpoutlet, said occluder wall preventing the flow of fluid through saidfluid exit passageway when pressed against the adjacent portion of saidhousing; and a catheter for directing medication to a specific locationwithin the body, said catheter having a catheter inlet in fluidcommunication with said pump outlet.
 10. A system as recited in claim 9,wherein said housing forms said resilient crown for said pump, and saidresilient crown overlies an extension of said floor plate to define saidpumping chamber therebetween.
 11. A system as recited in claim 9,wherein said receiving means comprises an injection site apparatusproviding a self-sealing dome overlying a rigid needle-shield to definean injection chamber therebetween, said needle-shield having an outletpassageway in open fluid communication with an outlet of said injectionsite apparatus so that said reservoir can be placed in fluidcommunication with said injection chamber.
 12. A system as recited inclaim 9, wherein said reservoir includes a flexible outer body capableof expanding to accommodate varying amounts of medication.
 13. A systemas recited in claim 9, including means for preventing the flow of fluidthrough said fluid exit passageway to fill said pumping chamber.
 14. Asystem as recited in claim 9, wherein said normally closed valveincludes a diaphragm displacement finger extending downwardly from theceiling of one of said chambers, said diaphragm displacement fingerbeing situated and configured to displace said valve diaphragm and opensaid normally closed valve to fluid flow therethrough when moved throughsaid valve passageway.
 15. A system as recited in claim 9, includingmeans for connecting any separately positioned components of said systemwith flexible, substantially inelastic tubing, said connecting meansincluding a connector assembly sealingly anchored at one end to acomponent of said system, said connector assembly including a connectorbody and a corresponding connector nut which can be threaded onto saidconnector body, said connector nut having an elastic sleeve positionedinternally therein through which an end of the flexible, substantiallyinelastic tubing is placed, which sleeve is compressible by theinteraction between said connector body and said connector nut to form afriction seal with the tubing and securely hold the same within saidconnector assembly.
 16. A subcutaneous infusion reservoir and pumpsystem, comprising:means for receiving medication into said system byinjection; a reservoir for storing medication injected into saidreceiving means; a catheter for directing the medication to a specificlocation in a body removed from said reservoir, said catheter having acatheter inlet and being positionable within the body independently ofthe position of said reservoir; means for subcutaneously conducting themedication from said reservoir to said catheter inlet; and means forpumping and controlling the flow of medication from said reservoir tosaid catheter, said pumping and controlling means forming a portion ofsaid conducting means and including a pump which is separated from saidreservoir and said catheter by other portions of said conducting means,wherein passage of medication through said pump is controlled by valvemeans situated adjacent an inlet and an outlet of said pump, and whereinone of said valve means comprises a normally closed valve.
 17. A systemas recited in claim 16, wherein the valve means includes a one-way valvein addition to the normally closed valve.
 18. A system as recited inclaim 16, wherein the normally closed valve is capable of being openedto fluid flow therethrough by percutaneous manual manipulation of saidpumping and controlling means, said normally closed valve having a valveinlet, a valve outlet, a housing forming an inlet chamber and an outletchamber, a valve passageway situated directly between said inlet andoutlet chambers, and a valve diaphragm situated within said housing andresiliently biased to cover said valve passageway, said valve diaphragmnormally forming a seal with a portion of said valve surrounding saidvalve passageway to prevent the flow of fluid through said normallyclosed valve unless forceably displaced.
 19. A system as recited inclaim 18, including means integrally formed with said pumping andcontrolling means for preventing the flow of medication therethroughwhen said normally closed valve is opened to fluid flow.